// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion It is a warning to use a null aware operator (?., ?.., ??, ??=,
/// or ...?) on an expression of type T if T is strictly non-nullable.
///
/// @description Check it is a warning to use a null aware operator (?., ?.., ??,
/// ??=, or ...?) on a strictly non-nullable receiver. Test <T extends Object>
/// @author sgrekhov@unipro.ru
/// @issue 39598
/// @issue 39714

test<T extends Object>(T t) {
  t?.toString();
// ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  t?..toString();
// ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  t ?? t;
//     ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  t ??= t;
//      ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  List<T> clist = [t, t];
  List<T> alist = [t, t, ...? clist];
//                       ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
}

main() {
  test<String>("Lily was here");
}